gender<-c('f','m','k','m','f','f','m','k','f','k')
age<-sample(1:100,10,replace = FALSE)
tapply(age, gender, mean)
height<-sample(150:190,10,replace = FALSE)
weight<-sample(50:90,10,replace = FALSE)
x<-data.frame(gender,age,height,weight)
print(x)